//
// Berlin Brown
// bigbinc@hotmail.com
// glDrawLib.cpp
//
// a couple of drawing routines
// opengl library
//

#include <stdio.h>
#include <stdlib.h>

#include <math.h>

#include <GL/gl.h>			// Header File For The OpenGL32 Library
#include <GL/glu.h>			// Header File For The GLu32 Library


#include "gldrawlib.h"


// Reduces a normal vector specified as a set of three coordinates,
// to a unit normal vector of length one.
void ReduceToUnit(float vector[3])
	{
	float length;
	
	// Calculate the length of the vector		
	length = (float)sqrt((vector[0]*vector[0]) + 
						(vector[1]*vector[1]) +
						(vector[2]*vector[2]));

	// Keep the program from blowing up by providing an exceptable
	// value for vectors that may calculated too close to zero.
	if(length == 0.0f)
		length = 1.0f;

	// Dividing each element by the length will result in a
	// unit normal vector.
	vector[0] /= length;
	vector[1] /= length;
	vector[2] /= length;
}	// end of the function


// Points p1, p2, & p3 specified in counter clock-wise order
void Calc_Normal(float v[3][3], float out[3])
	{
	float v1[3],v2[3];
	static const int x = 0;
	static const int y = 1;
	static const int z = 2;

	// Calculate two vectors from the three points
	v1[x] = v[0][x] - v[1][x];
	v1[y] = v[0][y] - v[1][y];
	v1[z] = v[0][z] - v[1][z];

	v2[x] = v[1][x] - v[2][x];
	v2[y] = v[1][y] - v[2][y];
	v2[z] = v[1][z] - v[2][z];

	// Take the cross product of the two vectors to get
	// the normal vector which will be stored in out
	out[x] = v1[y]*v2[z] - v1[z]*v2[y];
	out[y] = v1[z]*v2[x] - v1[x]*v2[z];
	out[z] = v1[x]*v2[y] - v1[y]*v2[x];

	// Normalize the vector (shorten length to one)
	ReduceToUnit(out);

} // end of the function


//
// Normalize
//
void Normalize(float p[3])
{
   float length;

   length = (float)sqrt((p[0] * p[0]) + (p[1] * p[1]) + (p[2] * p[2]));

   if (length != 0) {
      p[0] /= length;
      p[1] /= length;
      p[2] /= length;
   } else {
		p[0] = 0;
		p[1] = 0;
		p[2] = 0;
	}	

} // end of the function 



//
// calcnormal
//
void CalcNormal(float p[3],float p1[3],float p2[3], float n[3])
{
   float pa[3];
   float pb[3];
	
   pa[0] = p1[0] - p[0];
   pa[1] = p1[1] - p[1];
   pa[2] = p1[2] - p[2];

	pb[0] = p2[0] - p[0];
	pb[1] = p2[1] - p[1];
	pb[2] = p2[2] - p[2];

   n[0] = pa[1] * pb[2] - pa[2] * pb[1];
   n[1] = pa[2] * pb[0] - pa[0] * pb[2];
   n[2] = pa[0] * pb[1] - pa[1] * pb[0];

   Normalize(n);

} // end of the function



//
// get clock
//
unsigned long getclock(void)
{
// this function returns the current tick count

// return tim

//return(GetTickCount());

} // end Get_Clock


//
// Draw Objects
//
void DrawObjects(void)
{
	glLoadIdentity();									// Reset The Current Modelview Matrix
	glTranslatef(-1.5f,0.0f,-6.0f);						// Move Left 1.5 Units And Into The Screen 6.0
	//glRotatef(rtri,0.0f,1.0f,0.0f);						// Rotate The Triangle On The Y axis ( NEW )

	glBegin(GL_TRIANGLES);								// Start Drawing A Triangle
		glColor3f(1.0f,0.0f,0.0f);						// Red
		glVertex3f( 0.0f, 1.0f, 0.0f);					// Top Of Triangle (Front)
		glColor3f(0.0f,1.0f,0.0f);						// Green
		glVertex3f(-1.0f,-1.0f, 1.0f);					// Left Of Triangle (Front)
		glColor3f(0.0f,0.0f,1.0f);						// Blue
		glVertex3f( 1.0f,-1.0f, 1.0f);					// Right Of Triangle (Front)
		glColor3f(1.0f,0.0f,0.0f);						// Red
		glVertex3f( 0.0f, 1.0f, 0.0f);					// Top Of Triangle (Right)
		glColor3f(0.0f,0.0f,1.0f);						// Blue
		glVertex3f( 1.0f,-1.0f, 1.0f);					// Left Of Triangle (Right)
		glColor3f(0.0f,1.0f,0.0f);						// Green
		glVertex3f( 1.0f,-1.0f, -1.0f);					// Right Of Triangle (Right)
		glColor3f(1.0f,0.0f,0.0f);						// Red
		glVertex3f( 0.0f, 1.0f, 0.0f);					// Top Of Triangle (Back)
		glColor3f(0.0f,1.0f,0.0f);						// Green
		glVertex3f( 1.0f,-1.0f, -1.0f);					// Left Of Triangle (Back)
		glColor3f(0.0f,0.0f,1.0f);						// Blue
		glVertex3f(-1.0f,-1.0f, -1.0f);					// Right Of Triangle (Back)
		glColor3f(1.0f,0.0f,0.0f);						// Red
		glVertex3f( 0.0f, 1.0f, 0.0f);					// Top Of Triangle (Left)
		glColor3f(0.0f,0.0f,1.0f);						// Blue
		glVertex3f(-1.0f,-1.0f,-1.0f);					// Left Of Triangle (Left)
		glColor3f(0.0f,1.0f,0.0f);						// Green
		glVertex3f(-1.0f,-1.0f, 1.0f);					// Right Of Triangle (Left)
	glEnd();											// Done Drawing The Pyramid

	glLoadIdentity();									// Reset The Current Modelview Matrix
	glTranslatef(1.5f,0.0f,-7.0f);						// Move Right 1.5 Units And Into The Screen 7.0
	//glRotatef(rquad,1.0f,1.0f,1.0f);					// Rotate The Quad On The X axis ( NEW )

	glBegin(GL_QUADS);									// Draw A Quad
		glColor3f(0.0f,1.0f,0.0f);						// Set The Color To Blue
		glVertex3f( 1.0f, 1.0f,-1.0f);					// Top Right Of The Quad (Top)
		glVertex3f(-1.0f, 1.0f,-1.0f);					// Top Left Of The Quad (Top)
		glVertex3f(-1.0f, 1.0f, 1.0f);					// Bottom Left Of The Quad (Top)
		glVertex3f( 1.0f, 1.0f, 1.0f);					// Bottom Right Of The Quad (Top)
		glColor3f(1.0f,0.5f,0.0f);						// Set The Color To Orange
		glVertex3f( 1.0f,-1.0f, 1.0f);					// Top Right Of The Quad (Bottom)
		glVertex3f(-1.0f,-1.0f, 1.0f);					// Top Left Of The Quad (Bottom)
		glVertex3f(-1.0f,-1.0f,-1.0f);					// Bottom Left Of The Quad (Bottom)
		glVertex3f( 1.0f,-1.0f,-1.0f);					// Bottom Right Of The Quad (Bottom)
		glColor3f(1.0f,0.0f,0.0f);						// Set The Color To Red
		glVertex3f( 1.0f, 1.0f, 1.0f);					// Top Right Of The Quad (Front)
		glVertex3f(-1.0f, 1.0f, 1.0f);					// Top Left Of The Quad (Front)
		glVertex3f(-1.0f,-1.0f, 1.0f);					// Bottom Left Of The Quad (Front)
		glVertex3f( 1.0f,-1.0f, 1.0f);					// Bottom Right Of The Quad (Front)
		glColor3f(1.0f,1.0f,0.0f);						// Set The Color To Yellow
		glVertex3f( 1.0f,-1.0f,-1.0f);					// Top Right Of The Quad (Back)
		glVertex3f(-1.0f,-1.0f,-1.0f);					// Top Left Of The Quad (Back)
		glVertex3f(-1.0f, 1.0f,-1.0f);					// Bottom Left Of The Quad (Back)
		glVertex3f( 1.0f, 1.0f,-1.0f);					// Bottom Right Of The Quad (Back)
		glColor3f(0.0f,0.0f,1.0f);						// Set The Color To Blue
		glVertex3f(-1.0f, 1.0f, 1.0f);					// Top Right Of The Quad (Left)
		glVertex3f(-1.0f, 1.0f,-1.0f);					// Top Left Of The Quad (Left)
		glVertex3f(-1.0f,-1.0f,-1.0f);					// Bottom Left Of The Quad (Left)
		glVertex3f(-1.0f,-1.0f, 1.0f);					// Bottom Right Of The Quad (Left)
		glColor3f(1.0f,0.0f,1.0f);						// Set The Color To Violet
		glVertex3f( 1.0f, 1.0f,-1.0f);					// Top Right Of The Quad (Right)
		glVertex3f( 1.0f, 1.0f, 1.0f);					// Top Left Of The Quad (Right)
		glVertex3f( 1.0f,-1.0f, 1.0f);					// Bottom Left Of The Quad (Right)
		glVertex3f( 1.0f,-1.0f,-1.0f);					// Bottom Right Of The Quad (Right)
	glEnd();											// Done Drawing The Quad

} // end of the functino

